The opening batsman missed India's final Group B contest against West Indies after having an allergic reaction in his knee and is a doubt for the last-eight clash in Ahmedabad.

Captain Mahendra Singh Dhoni says a decision on the opener's fitness may be left as late as the morning of the match.

"We are taking a call (on Sehwag) in the evening or maybe tomorrow morning before the start of the game. Apart from that, all the others are fit," Dhoni said.

Sehwag made 175 against Bangladesh in the opening match of the tournament and also grabbed a half-century against South Africa before picking up the problem.

Short balls

"It's really good to have Sehwag opening the innings for you, because deliveries will be short and to the body or somewhere else. He's the kind of batsmen, if you are slightly wrong with it, he can make the most of that kind of a bowling," Dhoni added.

"It's really good to have him, he can play an aggressive game, change the course of a game in the first five overs, give your team the kind of momentum that is needed."

If Sehwag does not win his fitness race, India will likely retain Suresh Raina in the middle order, while Gautam Gambhir, promoted to open the innings against the Windies, will join Sachin Tendulkar at the top of the order.

Australia head into the contest on the back of a four-wicket defeat to Pakistan, a result which ended their incredible 34-match unbeaten run in World Cups.

And the three-time defending champions are slight underdogs to reach the semi-finals as they will have to deal with fervent home support at Sardar Patel Stadium.

Unchanged

Australia, meanwhile, have named an unchanged team for the past three matches and captain Ricky Ponting says his side will be relying on the likes of pacemen Brett Lee, Shaun Tait and Mitchell Johnson again.

"No doubt we rely on our fast bowlers to take the wickets and India are probably the exact opposite of that," he said.

"Looking at their last match, it was probably in the 26th-27th over before (pace bowler) Munaf Patel got to bowl. We have an idea of what to expect tomorrow.

"Probably they would open with Zaheer Khan and one of the spinners with the new ball and bring their spinners early on.

"We could be facing 30 overs of spin bowling and they will probably face 30 overs of fast bowling."